RU58840U1 - MULTI-LAYER HOUSING SCREEN SEMICONDUCTOR CONVERTER - Google Patents

Abstract

The utility model relates to electrical engineering and can be used in the manufacture of housings of semiconductor converting devices with increased requirements for acceptable levels of radio noise and noise immunity to extraneous electromagnetic fields during operation. A method of manufacturing a multilayer case - screen of a semiconductor device is that a thin layer of ceramic material with high dielectric constant is initially applied to the main metal case of the device, over which a metal layer with high electrical conductivity is deposited by sputtering, and connected to a metal conductor, which is connected to metal tire. On top of the sprayed metal layer, a metal cap is installed, made with a uniform gap over the entire outer surface of the main body of the converter device, which is filled with a ferromagnetic absorbing layer obtained by mixing the epoxy compound with a hardener and calibrated powder of a ferromagnetic filler, heated and baked until the binder is completely polymerized. Due to the formation of a multilayer case - screen of a semiconductor converter, external electromagnetic fields are initially reflected from the outer metal cap, and part of the electromagnetic waves penetrating through the outer metal cap is broken by the ferromagnetic absorbing layer and partially absorbed by it. That part of the "broken" electromagnetic waves that penetrated through the ferromagnetic absorbing layer is partially reflected from the sprayed metal layer, and partially forms eddy currents in the metal layer and parasitic pickups drain to the ground through the connected conductor. The remainder of the energy of electromagnetic waves passing through a layer of ceramic

materials with high dielectric constant are also partially absorbed, and reflected from the main body of the semiconductor converter device due to multiple re-reflections with simultaneous partial absorption completely dissipate and turn into heat. In the thus constructed multilayer case - screen, the intrinsic electromagnetic radiation of the semiconductor converter device is scattered similarly to those discussed above, as well as external electromagnetic influences.

Description

The utility model relates to electrical engineering and can be used in the manufacture of housings of semiconductor converting devices with increased requirements for acceptable levels of radio noise and noise immunity to extraneous electromagnetic fields during operation.

A known electromagnetic screen of an alternating electromagnetic field [1], in which to increase the efficiency of shielding from the external and internal surfaces of the walls of the housing, ferromagnetic elements are installed, this leads to the formation of a two-layer magnetic screen. The screening efficiency of such a two-layer screen increases with increasing distance between its ferromagnetic layers.

However, to obtain high shielding efficiency in this design of the electromagnetic shield, it is necessary to significantly increase the dimensions of the housing of the semiconductor converter device, which is not always acceptable, since the main trend in semiconductor technology is aimed at miniaturization of these devices.

Known ferromagnetic screen [2], which is taken as a prototype. To increase the efficiency of shielding inhomogeneous magnetic fields in this design, a ferromagnetic filler is placed in the hollow shell of the screen, containing a fine fraction, the percentage of which is 25-75% of the mixture volume and a large fraction is a fraction of ferromagnetic material with a diameter of 0.4-3.5 mm.

However, in this design of the ferromagnetic screen, due to the flowability of the components of the fine and coarse fractions, inhomogeneous regions can arise in the hollow shell of the screen, which reduces the shielding efficiency.

The purpose of the proposed utility model is to ensure uniform shielding efficiency of the semiconductor converter device in the frequency spectrum protected from radio interference.

This goal is achieved in that the method of manufacturing a multilayer case-screen of a semiconductor converter device includes installing a case of two metal walls between which a ferromagnetic absorbing layer is placed, according to a utility model, a thin layer of ceramic material with high dielectric constant is initially applied to the main metal case of the semiconductor converter device over which a metal layer with high electrical conductivity is applied by sputtering, and connected to a metal conductor, which is connected to the grounding bus, and on top of the sprayed metal layer, a metal cap, made with a uniform gap, is installed over the entire outer surface of the main body of the converter device, which is filled with a ferromagnetic absorbing layer made by mixing epoxy compound with a hardener and calibrated powder of a ferromagnetic filler, heated and baked until the binder is fully polymerized.

Due to the formation of a multilayer case - screen of a semiconductor converter, external electromagnetic fields are initially reflected from the outer metal cap, and part of the electromagnetic waves penetrating through the outer metal cap is broken by the ferromagnetic absorbing layer and partially absorbed by it. That part of the "broken" electromagnetic waves that penetrated through the ferromagnetic absorbing layer is partially reflected from the sprayed metal layer, and partially forms eddy currents in the metal layer and parasitic pickups drain to the ground through the connected conductor. The rest of the energy of electromagnetic waves passing through a layer of ceramic material with high dielectric constant is also partially absorbed, and reflected from the main body of the semiconductor converter due to multiple reflections with simultaneous

partial absorption completely dissipate and turn into heat. In the thus constructed multilayer case - screen, the intrinsic electromagnetic radiation of the semiconductor converter device is scattered similarly to those discussed above, as well as external electromagnetic influences.

Figure 1 shows a fragment of the cross section of a multilayer case - the screen of a semiconductor converter, where 1 is a metal base, 2 is a metal main body, 3 is a ceramic material with high dielectric constant, 4 is a sprayed metal layer, 5 is a connecting conductor, 6 is grounding bus, 7 - calibrated ferromagnetic layer, 8 - metal cap.

For the manufacture of a multilayer case - screen of a semiconductor converter device, the metal base 1 and the main metal case 2 are performed by stamping. Then, a thin layer of ceramic material 3 with high dielectric constant is applied to the main body 2 from the outer surface by any known method, for example, by a plasma-chemical method in an argon gas medium. Next, a metal layer 4 is applied to the ceramic material 3 by vacuum spraying, to which the connecting conductor 5 is soldered, which is subsequently connected to the grounding bus 6 when collecting the converter circuit diagrams.

Then, powder ferromagnetic material is taken and sieved through a calibration sieve, for example, 0.5-0.75 mm. The sieve size is selected according to the required thickness of the obtained ferromagnetic absorbing layer 7. The calibrated ferromagnetic material is thoroughly mixed with an epoxy compound and hardener heated to 70-80 ° C. to the required uniform consistency of the dielectric mass. Next, on the metal cap 8, which is manufactured by stamping, the obtained dielectric mass is applied from the inside and the main metal body 2 with the applied ceramic layer 3 and the metal layer 4 is installed by pressing it. Injection removes the excess dielectric mass and fixes the required thickness

ferromagnetic absorbing layer 7. Then bake at 140-150 ° C for 6 hours until the polymerization of the binder.

Thus, we got a multilayer screen housing for a semiconductor converter, which provides uniform and effective shielding of our own electromagnetic radiation, as well as from external electromagnetic fields in the protected radio frequency range due to multiple reflections with simultaneous partial absorption of electromagnetic wave energy, completely dissipates and turns into heat. which provides increased electromagnetic compatibility of electronic systems located in immediate proximity, both among themselves and with other electrical devices.

Literature:

1. A.S. 1626475 USSR, MKP 5 N 05 K 9/00, G 12 V 17/00. Claim 12/22/88. Publ. 02/07/91. Bull. No. 5.

2. A.S. 1594616 USSR, MKP 5 G 12 V 17/02, G 01 R 1/18. Claim 07.07.87. Publ. 09/23/90. Bull. Number 35

Claims (1)

A multilayer screen housing of a semiconductor converter device, comprising mounting a case of two metal walls between which a ferromagnetic absorbing layer is placed, characterized in that a thin layer of ceramic material with high dielectric constant is initially installed on the main metal case of the semiconductor converter device, on top of which a metal layer is installed with high electrical conductivity and connected to a conductor that connect to the grounding bus, and on top of the metal layer, a metal cap is installed, made with a uniform gap over the entire outer surface of the main body of the converter device, this gap is filled with a ferromagnetic absorbing layer, which is made by mixing an epoxy compound with a hardener and a calibrated ferromagnetic filler powder and baked until complete polymerization binder.